During the last decade the recombinant technology has provided new high yield processes allowing a variety of products to be obtained in high purity in an industrial scale. Among such products are lipases. These lipases have found different technical applications, e.g. in ester hydrolysis processes, ester synthesis processes, ester interchange reactions or within the detergent industry. However, these recombinantly produced microbial lipases have never found therapeutical applications.
For pancreatic enzyme replacement therapy lipase containing pharmaceutical preparations are available. Most of these preparations are mixtures of the various enzymes, proteases, amylases and lipases, along with other components, as the manufacture of these preparations is based mainly on extraction of porcine pancreatic enzymes. Such substitution preparations are expensive, and the therapeutic effect varies considerably within the preparations. Especially the amount of lipase in most preparations is too low to ensure adequate enzymatic degradation of the triglycerides in order to achieve a normal lipid absorption from the gastrointestinal tract. Furthermore the US FDA, in a press release of May 16, 1990 (P90-31), and a Federal Register Notice of Proposed Rule Making of the same date (FR 20434-20438), propose to ban a number of these enzymes sold as digestive aids, as the administration claims that these ingredients had not been proven effective.
Other lipase containing pharmaceutical preparations are based on lipases produced by microbiological cultivation of lipase producing fungi followed by recovery of the lipases from the culture broth, vide e.g. DE publication No. 16 42 654 and GB publication No. 1 442 677. These processes are low yield processes, causing a troublesome and uneconomic isolation and purification of the desired lipase.
From international patent application WO 86/01532 a human gastric lipase protein is known. Moreover, a process for producing this protein using recombinant DNA technology is described. Gastric lipases are of course of animal origin. Problems inherently associated with the expression of genes of animal origin in microorganisms compromise the use of many such processes in industrial scale. In these cases troublesome and uneconomic isolation and purification processes are still required to obtain a sufficiently purified lipase.
Oral substitution of exocrine pancreatic enzymes is of key importance in the treatment of humans suffering from severe exocrine pancreatic insufficiency, such as cystic fibrosis and chronic pancreatitis, which lead to malabsorption and steatorrhoea (fatty stools). Treatment improves the frequency, nature and size of the stools, but steatorrhoea is rarely abolished. Although conventional enzyme preparations can largely abolish protein and carbohydrate maldigestion, they are only partially able to improve the digestion of fats. The major reason for this failure of theoretically adequate dosages of conventional pancreatic enzyme preparations to completely eliminate steatorrhoea has been found to be inactivation of the lipase by gastric acid and pepsin.
Therapeutic alternatives for supplementary therapy with conventional pancreatic enzyme preparations are acid stabilized or acid protected preparations. However, due to a generally decreased pH in the duodenum and small intestine in patients suffering from cystic fibrosis, enteric coated preparations may not release their content in an ordinary manner.
As an overall, treatment by conventional pancreatic enzyme preparations brings about serious disadvantages for the patients, as unpleasantly high amounts of granulate/capsules are required, causing nausea and reduction of appetite, yet not leading to total improvement.
It is an object of the present invention to obviate these shortcomings by providing recombinantly produced microbial lipases of high purity for the manufacture of pharmaceutical compositions, with increased lipase content.